Mining and ore-processing require a huge amount of energy for operating machinery, transportation, and, especially, for smelting and refining. That includes about 15% of total global electricity and 11% of total global energy overall, and therefore acquiring the metals used to make all the things we buy has a huge climate impact. We need to think carefully about that every time we buy something that has metal in it. And, of course, we need to think about that every time we buy a manufactured product that has anything in it.
Recovering fossil fuels is also energy intensive and leads to emissions of greenhouse gases at every step in the process, but the really significant climate cost of fossil fuels is in their use, and that’s why we can no longer consider fossil fuels as an energy source for the future, and we have to stop looking for and developing more fossil fuel resources right now.
Mining and ore-processing have implications for Earth systems in a number of ways:
- Mining results in exposure of rock to weathering, both within the mines (especially surface mines) and because ore-processing involves crushing and grinding rock into small pieces, producing waste materials that are highly susceptible to weathering.
- Weathering includes oxidation of sulphide minerals, releasing acid into the environment, leading to some of the outcomes summarized in Box 8.1, and might also include hydrolysis of silicates, in which case it could consume CO2 from the atmosphere.
- Refining metals (especially smelting) introduces a wide range of toxic materials into the atmosphere, as well as acidity, that can have significant negative for plant life, and so for ecosystems in general.
- Production of cement by heating of calcium carbonate results in the release of carbon dioxide, and so contributes to climate change.
- Mining, and the related construction of roads and railways, contributes to slope failures and that can have a range of Earth systems implications, some of which are described in Chapter 1.
- Igogo, T. et al. (2020). Integrating clean energy in mining operations: Opportunities, challenges, and enabling approaches (technical report, NREL/TP-6A50-76156). The Joint Institute for Strategic Energy Analysis (JISEA). https://www.nrel.gov/docs/fy20osti/76156.pdf ↵